Determination of the lead and cadmium burden in some northeastern Atlantic and Mediterranean fish species by DPSAV

Lead (Pb) and cadmium (Cd) contents in the edible parts (muscle, fillet) of 68 commercially used fish species from two European regions, the northeastern Atlantic (Tampen, north of the Shetland Islands, Faroe Islands and Copinsay) and the Mediterranean (Izmir Outer Bay, Homa Lagoon/Izmir and Mersin Bay), were determined by means of differential pulse stripping anodic voltammetry. In the sample preparation step, all frozen fish samples were lyophilised, milled in a ball mill and finally decomposed in an oxygen plasma ashing chamber. Among the fishes from northeastern Atlantic waters, the highest average Pb concentration belonged to those from Tampen with 11.25 µg/kg and the average Cd concentration to fish from Copinsay with 2.23 µg/kg. For the Mediterranean fishes, the highest average Pb and Cd concentrations belonged to those from Mersin Bay, with 185.39 µg/kg and 2.12 µg/kg, respectively. The accuracy of the concentrations determined in this study was checked by measurements of the certified reference material CRM No 422 cod muscle from the Commission of the European Communities, Community Bureau of Reference. All Cd and Pb concentrations observed in species of the eastern Mediterranean and the northeastern Atlantic were below the maximum permitted national Turkish and European levels.     

Retention of health-related beneficial components during household preparation of selenium-enriched African catfish (Clarias gariepinus) fillets

Industrial processing and heat treatment of fish muscle generally lead to losses of water-soluble components, some of which may have beneficial health effects. The aim of this work was to determine the retention of taurine, selenium and n-3 polyunsaturated fatty acids when preparing African catfish by three traditional household techniques: boiling in pouches, deep-frying and baking. Cooking did not significantly reduce the content of selenium, having retention between 91and 104%. Deep-frying resulted in a taurine loss of 40%, which was significantly higher than in baking where losses were 25% The fatty acid profiles were similar for baked and boiled fillets, but were significantly different from deep-fried fillets, due to absorption of vegetable frying oil. Baking was the best preparation technique with regard to retention of 20:5n-3 (eicosapentaenoic acid; EPA) and 22:6n-3 (docosahexaenoic acid, DHA), retaining above 80% for both fatty acids, whereas boiling and deep-frying were able to retain only approximately 54 and 65% of each, respectively.